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Author

Date Permissions Signed

Date of Award

Document Type

Masters Thesis

Degree Name

Master of Science (MS)

Department

Environmental Studies

First Advisor

Bach, Andrew J.

Second Advisor

Homann, Peter S., 1953-

Third Advisor

Clark, Douglas H., 1961-

Abstract

Glacial forelands are harsh environments where incipient pedogenesis provides the basis for vegetation establishment and succession. Myriad local factors make discerning major influences on this process difficult. The Easton foreland on Mt. Baker, Washington, was investigated, where till has been deposited over the last one-hundred years. Easton foreland soils were sampled for in situ characteristics and laboratory measures, creating a multi-variable dataset of quantitative and qualitative data. It was hypothesized that soil development, including organic matter content, carbon, nitrogen, the carbon to nitrogen ratio (C/N), and pH, would show a trend when compared to indicators of development: time, elevation, and successional stage. Furthermore, it was posited that pedogenesis would be categorical, roughly defined by vegetation zones as opposed to incremental, continuous development through the valley. Sites were selected on glacial till, intentionally avoiding confounding fluvial and colluvial influences. To determine the approximate surface age of each sample site, historic and air photos were used as well as existing literature on the recent glacial history of Mt. Baker. It was found that the Easton sequence was best indicated by stages of vegetation succession (Vegetation Zones), with strong correlation to nearly all dependent variables. An intertwined toposequence was also informative as a more continuous and quantitative independent variable to complement Deglaciation Age. The Easton's glacial history is complicated by the 1950s-80s re-advance, creating a nonlinear spatial timeline and limiting its usefulness as in indicator of development; correlation results were low for the chronosequence. These results reinforce a geoecological viewpoint of categorical landscape development, with the Easton showing facilitative and patchy succession best represented by four Vegetation Zones. This discontinuous facilitation is likely due to seed rain and detritus input from the mature forests atop adjacent Holocene moraines (Railroad Grade and Metcalfe). This Cascadian system was found to be similar to other studied foreland, however there are some differences worth noting and are discussed in Chapters 4 and 5. This sequence of soil development showed trends in nearly all dependent variables, with organic matter, carbon, nitrogen, and carbon/nitrogen ratio all increasing with surface age, successional stage, and decreasing with elevation. My study sought to understand a Cascadian foreland and to assess it in the context of other studied glacial forefields in order to better understand the pedogenic processes that shape these unique environments.

Type

Text

Publisher

Western Washington University

OCLC Number

864907441

Digital Format

application/pdf

Geographic Coverage

Baker, Mount (Wash.)

Genre/Form

Academic theses

Language

English

Rights

Copying of this thesis in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this thesis for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.